regulator: qcom: labibb: Constify static structs

regulator: qcom: labibb: Constify static structs

The only usage of qcom_labibb_ops is to assign it to the ops field in
the regulator_desc struct, which is a const pointer. The only usage of
pmi8998_lab_desc and pmi8998_ibb_desc is to assign their address to the
desc field in the labibb_regulator_data struct which can be made const,
since it is only copied into the desc field in the
labbibb_regulator_data struct. This struct is modified, but that's a
copy of the static one. Make them const to allow the compiler to put
them in read-only memory.

Signed-off-by: Rikard Falkeborn <rikard.falkeborn@gmail.com>
Link: https://lore.kernel.org/r/20200930162602.18583-1-rikard.falkeborn@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>